Explanation:
On March 17, the
MESSENGER spacecraft became the first
to orbit Mercury, the solar system's
innermost planet.
This is its
first processed color image
since entering Mercury orbit.
Larger, denser, and with almost twice the surface gravity of
Earth's moon,
Mercury still looks moon-like at first glance.
But in this view its terrain shows light blue and brown areas near
craters and long bright rays of material streaking the surface.
The prominent bright ray crater Debussy at the upper right
is 80 kilometers (50 miles) in diameter.
Terrain toward the bottom of
the historic image
extends to Mercury's south pole and
includes a region
not previously imaged from space.